The invention relates to an ultrasonic sensor with a cylinder-shaped housing the base of which forms a diaphragm of the ultrasonic sensor. In addition the invention relates to a method for the manufacture of such an ultrasonic sensor. Such ultrasonic sensors are more preferably employed in automobiles and for distance measurements.
Ultrasonic sensors of the type mentioned at the outset are known for example from DE 10 2004 031 310 A1, EP 1 443 342 A1 and WO 2005/024451 A2.
There it is known to use aluminium cups, wherein a piezoelectric sensor is glued to the base from the inside. The base of the aluminium cup then forms an outer aluminium diaphragm which in part is adjusted to the directivity pattern in a grinding process. For contacting the piezoelectric crystals which are formed as piezoelectric disc a cable or lead frame is produced and soldered in manually. The entire cup-shaped sensor element is then cast-embedded. This is then followed by additional contacting with a circuit board circuit and the circuit board and the entire sensor arrangement are inserted in a plastic housing and cast-embedded once more.
Another concept of an ultrasonic sensor is known from DE 100 23 065 B4. Here, a diaphragm is initially held in a diaphragm holder which is held in a housing by way of a carrier element.